Preparation And Properties Of Polyaniline Grafted Graphene Composites

Graphene and polyaniline composites with good capacitance properties has been widely used as the electrode materials of supercapacitors.However,non-covalently connected polyaniline and graphene in the composites leads to a poor electrochemical cycle stability due to the easy detachment of polyaniline from graphene surface during use.The conductive thermal stability of the inorganic acid-doped graphene and polyaniline composites was poor and would impair its application performance when the composite was coated on the fabric.Herein,the covalently graft composite of graphene and polyaniline was designed to improve the cycle stability and electrical performances.On this basis,the polyaniline in the composite material was doped with citric acid to further improve the conductive thermal stability of the composite material.It was applied to the coating finishing of polyester fabric to impart the fabric with good electrical conductivity,which is expected to be an electrode of the fabric-based supercapacitor.The research mainly contains two parts and they are shown as follows:1.Preparation and characterization of polyaniline grafted graphene composites.In order to improve the electrochemical cycle stability of polyaniline and graphene composites,polyaniline grafted graphene?rGO-PANI?composites was prepared.The graphene oxide?GO?was prepared by modified hummers method.The sulfoxide chloride was used for the acylating chlorination of carboxyl groups on GO and simultaneousreductionofotheroxygen-containinggroups.Then,Amino-graphene?rGO-NH₂?,an intermediate product,was obtained from the amination of acyl chloride.On this basis,polyaniline grafted graphene?rGO-PANI?composite was prepared by in situ oxidation polymerization of aniline.The morphology and structure were characterized by scanning electron microscopy?SEM?,infrared spectroscopy?FTIR?,X-ray diffraction?XRD?,Raman spectroscopy?Raman?and ultraviolet-visible spectroscopy?UV-vis?.The conductivity was measured using four probes and the electrochemical performance was tested by electrochemical workstation.The non-grafted polyaniline/graphene composite?rGO/PANI?was also fabricated for comparison.Meanwhile,the effects of the mass ratio of aminated graphene and aniline on the morphology and electrical application properties of the composites were investigated.The results showed that polyaniline was covalently bonded to graphene in the composite.The cycling stability of the polyaniline grafted graphene composite was improved.The capacitance of rGO-PANI lost only 5%when the capacitance of rGO/PANI lost 15%after 100 cycles.The rGO-PANI composites had a good electrical performance.When the mass ratio of aminated graphene to aniline was 1:30,the resistivity and the mass ratio capacitance could reach to 0.3?·cm and 603F/g,respectively.2.Preparation and application of citric acid doped polyaniline grafted graphene composites.In order to improve the thermal stability of the composite material,the citric acid doped polyaniline grafted graphene was prepared.The graphene oxide?GO?was prepared by modified hummers method.The sulfoxide chloride was used for the acylating chlorination of carboxyl groups on GO and simultaneous reduction of other oxygen-containing groups.Then,Amino-graphene?rGO-NH₂?,an intermediate product,was obtained from the amination of acyl chloride.On this basis,according to the optimized mass ratio of the aminated graphene to aniline composites,the citric acid doped polyaniline grafted graphene?C-rGO-PANI?was prepared by in situ oxidative graft polymerization using the citric acid as the doping acid.Then it was applied to the coating finishing of polyester fabrics.The conductivity,the electrochemical performance and the thermal stability of the C-rGO-PANI composites were measured by four probes,the electrochemical workstation and the thermal gravimetric analyzer respectively.These performances also compared with the rGO-PANI composites.The structure and morphology of the coated fabrics of C-rGO-PANI composites were characterized by FTIR and SEM.The electrical and mechanical properties of the coated fabrics were tested.The results showed that the thermal stability of citric acid doped composites was significantly improved,which was beneficial for the coating finishing of fabrics under high temperature conditions.The conductivity and the mass specific capacitance of the C-rGO-PANI composites were 0.1?·cm and 645F/g,which were higher than those of rGO-PANI composites.After the C-rGO-PANI composite material was coated to the polyester fabric,the surface resistivity of the fabric was 2.3×10 ⁶?and the tensile stress was 70.5MPa.The surface resistivity of the coated fabric was reduced by 7 orders of magnitude and the tensile stress was slightly improved.The research showed that polyaniline grafted graphene composites had a good cycle stability and fine conductivity and the electrochemical performance.The citric acid doped polyaniline grafted graphene composites had a good thermal decomposition stability and conductivity and the electrochemical performance.When the citric acid doped polyaniline grafted graphene composites was applied to the polyester fabric coating finishing,the coated fabric showed a good conductivity,indicating that the composite has great application prospects in the preparation of fabric-based supercapacitors.